tolong dibantu soal latihan 7 a dan b

a) 2 sin x = -2
sin x = -1
Sin x = sin 270°
x = 270° = (270°/180°)π = (3/2)π
HP = {3/2 π}

b) cos x = -1/2
Cos x = cos 120°
x = 120° + k . 360° atau x = -120° + k . 360°
x = 120° ........................... x = -120° (TM) => untuk k = 0
x = 480° (TM) ................ x = 240° => untuk k = 1
HP = {120°, 240°} = {2/3 π, 4/3 π}